Acid Azine Dye Shading Composition for Cotton
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Solution Overview
Problem
Garments tend to yellow over multiple wash cycles, and existing dyes either build up on fabrics, leading to overshading or fail to provide a true blue or violet shade on cotton while also depositing on nylon, which results in unsatisfactory aesthetic outcomes.
Innovation Solution
A laundry treatment composition comprising an acid azine dye with a specific core structure, surfactants, and optional hydrophobic or direct dyes, applied in an aqueous solution at controlled pH and temperature to selectively deposit on cotton while minimizing deposition on nylon, maintaining the white appearance and preventing long-term yellowing.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If direct dyes are used for shading, then blue or violet colour is achieved on cotton, but the dye builds up over multiple washes leading to strong colour on the garment
Solution Approach 1:
The patent segments the dyeing function by using different dye classes for different fibre types: acid azine dyes for cotton (which do not build up) and direct dyes for nylon (which provide good colour but would build up on cotton). This segmentation allows each dye to perform its optimal function on the appropriate fibre without the negative buildup effect on cotton.
Solution Approach 2:
The patent changes the chemical parameters of the dye by selecting acid azine dyes with specific molecular structures (formula I) that have different affinity characteristics compared to conventional direct dyes. These parameter changes in dye chemistry enable selective deposition on cotton while preventing the buildup problem associated with direct dyes.
2Quantity of substance
If acid dyes are used for shading, then the dye does not build up over multiple washes, but no single acid dye provides high deposition to cotton with a true blue or violet shade
Solution Approach 1:
The patent uses composite dye formulations combining acid azine dyes (for cotton affinity and stability) with direct dyes or hydrophobic dyes (for enhanced colour strength and true blue/violet shade). This composite approach allows the acid azine dye to provide stability while the additional dye components compensate for any shade deficiencies, achieving both durability and colour accuracy.
3Quantity of substance
If acid dyes that deposit well on cotton are used, then high deposition is achieved, but the dye also deposits on nylon leading to overshading after multiple washes
Solution Approach 1:
The patent applies local quality by selecting dyes with fibre-specific affinity: acid azine dyes have local preference for cotton fibres due to their chemical structure and bonding mechanisms, while minimizing interaction with nylon. This local specificity ensures high deposition on the target fibre (cotton) while avoiding harmful deposition on non-target fibres (nylon).
Solution Approach 2:
The patent uses surfactants as intermediary substances to modify the interaction between the acid azine dye and the fabric. The surfactant acts as a mediator that enhances the selective binding of the dye to cotton while preventing unwanted deposition on nylon, thereby resolving the overshading problem.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The solution effectively provides a true blue shade on cotton without building up over multiple washes and minimizes overshading on nylon, maintaining the aesthetic value of garments by using acid azine dyes in combination with surfactants and other dyes to counteract yellowing.
Implementation Method 1
some acid azine dyes whilst depositing well on cotton substrates deposit poorly on nylon
Implementation Method 2
a laundry treatment composition comprising: (i) from 2 to 70 wt % of a surfactant, and from 0.0001 to 0.1 wt % of an azine dye
Data Source
AI summary
A laundry treatment composition comprising: (i) from 2 to 70 wt % of a surfactant, and from 0.0001 to 0.1 wt % of an azine dye, wherein the dye is of the following core structure (I), wherein Ra, Rb, Rc, and Rd are selected from: H, an branched or linear C1 to C7-alkyl chain, benzyl a phenyl, and a naphthyl; the dye is substituted with at least one SO3− or —COO− group; the B ring does not carry a negatively charged group or salt thereof; and the A ring may further substituted to form a naphthyl; the dye is optionally substituted by groups selected from: amine, methyl, ethyl, hydroxyl, methoxy, ethoxy, phenoxy, Cl, Br, I, F, and NO2.